GB2144586A - A transformer bobbin - Google Patents

Abstract

A transformer bobbin (2) has a hollow coil portion (4) for receiving a wound coil, and at least one terminal block (10, 12), the terminal block having a plurality of spaced apart apertures (14) for receiving terminal pins (16). The terminal block is also provided with a plurality of outwardly projecting separator members (30) which are positioned one in front of each aperture (14) and which are for separating wires for connection to the terminal pins (16). <IMAGE>

Description

SPECIFICATION A transformer bobbin This invention relates to a transformer bobbin.

Transformer bobbins are used to support the wound coils in trnnsforrners and are well known. The winding of the coils on the transformer bobbins can, however, be time consuming. Transformer bobbins usualy incorporate a terminal block in which may be secured a series of terminal pins, and the ends of the wires forming the coils of the transformer may be connected to these pins. The bobbins may also include separator members which may be employed in the terminal blocks for separating the ends of the wires which form the wound coils. Attempts to fully automate the winding of the coils on the bobbins has been frustrated by the coil winding apparatus having a tendency to foul the separator members.

It is an aim of the present invention to provide a transformer bobbin which reduces or obviates the above mentioned problem so that a wound coil can be provided on a hollow coil portion of the transformer bobbin by substantially fully automated coil winding apparatus.

Accordingly, this invention provides a transformer bobbin comprising a hollow coil portion for receiving a wound coil, and a terminal block having separator members and apertures for receiving terminal pins, wherein the separator members are located between the apertures and the hollow coil portion.

Hitherto, the terminal blocks have had the terminal pins positioned one in each of a plurality of the separator members, and the separator members have been separated from each other by slots. With the present invention, the provision of the terminal pins in the terminal block but not in the separator members is itself a radical departure from the well established transformer bobbin design. The provision of the separator members in front of the apertures for the terminal pins is a further radical departure from the established transformer bobbin design. The two design departures together enable a much wider space to be achieved between adjacent separator members than in the known transformer bobbins.

This larger spacing can then accommodate a pen-type coil winding apparatus, which could not be accommodated by the existing slots in the known and well established transformer bobbins. Thus the desired automated winding of the coils on the transformer bobbins can be achieved.

Usually, the transformer bobbin will be formed as a moulding of an electrically insulating material, the core portion, the terminal block and the separator members being integrally formed with each other.

Usually, there will be two terminal blocks and there may be seven or eleven terminal pins in the or each terminal block.

The terminal pins may be made from electro-soldar coated copper wire and, advantageously, the terminal pins are self-locking terminal pins of the type described and claimed in our co- pending Patent Application No.

8231822. Other types of terminal pins may however be employed if desired and for example, the terminal pins may have small swaged portions to enable them to be retained in their apertures.

The transformer bobbin may include the terminal pins and/or the wound coil.

The wound coil may be wrapped in an insulating tape.

The transformer bobbin may include soft iron laminations positioned in the core portion The soft iron laminations may be interlocking C-shaped laminations which interlock to form a rectangle.

The wrapped coil and the soft iron laminations may be coated in a resin or a varnish.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawing which is an isometric view of a transformer bobbin.

Referring to the drawing, there is shown a transformer bobbin 2 comprising a hollow coil portion 4 for receiving wound coils (not shown) on its surface 6. The coil portion 4 is provided with a circumferential upstanding wall member 8 for enabling the coils to be wound on the coil portion 4 in clockwise and anticlockwise directions.

The transformer bobbin 2 further comprises a pair of terminal blocks 10, 1 2. In the bobbin shown, each terminal block 10, 1 2 has seven spaced apart apertures 14, each for receiving a terminal pin, one of which terminal pins is shown schematically as terminal pin 1 6. The terminal pin 1 6 has an upper portion 18 which, when the pin in posiioned in an aperture 14 projects above the upper surface 20 of the terminal blocks 10, 1 2. The upper portion of apertures 1 4 are of greater diameter than the lower portion and each terminal pin 1 6 has a kinked portion 22 which locates inside the upper portion of apertures 1 4 such that the terminal pins self lock in the apertures 14.The pin 1 6 also has a lower portion 24 which locates in and projects from the lower part of the aperture 14 which is formed as a slot 26. The portion 24 extends at right angles to the surface 28 surrounding the slot 26.

The terminal blocks 10,12 further comprise a plurality of separator members 30 which, as shown, are positioned between the apertures 1 4 and the coil portion 4. The separtor members 30 are for separating wires (not shown) which may be connected to the terminal pins 16. Normally, the wires for connection to the various terminal pins 1 6 must be kept separate from each other as otherwise electrical short-circuiting may occur.

It will be noticed that slots 32 between the separator members 30 are relatively wide and, in the embodiment shown, have a width approximately twice the diameter of the widest portion of the apertures 14 which receive the kinked portion 22 of the terminal pins 16.

This is approximately twice the spacing achievable between adjacent separator members 30 are extremely useful because the coils can be wound on the surface 6 of the coil portion 4 from pen-like coil winding apparatus as the tip of the pen-like coil winding apparatus may be accomodated by the slots 32 between the separator members 30 with hitherto transformer bobbins. These wider slots between the separator members 30 without fouling on the separator members 30, as was hitherto often the case. Then the wound coils can be provided on the transformer bobbin 2 by a substantially fully automated and speedy process.

Usually, the hollow centre 34 of the coil portion 4 will be provided with soft iron laminations which may comprise C-shaped laminations which are arranged to interlock to form annular laminations of rectangular shape.

The terminal blocks 10,1 2 terminate in apertured portions 36 which are each provided with a mounting hole 38 which can be employed for mounting the transformer bobbin to a printed circuit board (not shown). The portion 36 at the end of the terminal block 10 is also provided with a blind hole 40 which may be used to support the transformer bobbin 2 when the bobbin is to be dipped in shellac or other resin.

Flanges 42 are used to help to contain the wiring coils.

It is to be appreciated that the embodiment of the present invention described above has been given by way of example only and that the modifications may be effected. Thus, for example, the holes 38 can be dispensed with and the end portions 36 may be of a shape other than that shown in the accompanying drawing.

Claims (11)

1. A transformer bobbin comprising a hollow coil portion for receiving a wound coil, and a terminal block having separator members and apertures for receiving terminal pins, wherein the separator members are located between the apertures and the hollow coil portion.

2. A bobbin according to claim 1 wherein the terminal block is formed integrally with the coil portion.

3. A bobbin according to claim 1 or claim 2 wherein the coil portion and the terminal block are moulded from an electrically insulating material.

4. A bobbin according to any one of claims 1 to 3 wherein there are two terminal blocks.

5. A bobbin according to any one of the preceding claims wherein each terminal block has seven apertures.

6. A bobbin according to any one of claims 1 to 4 wherein each terminal block has eleven apertures.

7. A bobbin according to any one of the preceding claims incuding soft iron laminations located in the hollow coil portion.

8. A bobbin according to claim 7 wherein the soft iron laminations comprise C-shaped laminations arranged to interlock to form annular laminations of rectangular shape.

9. A bobbin according to any one of the preceding claims including the wound coil and the terminal pins.

10. A bobbin according to claim 9 wherein the terminal pins are arranged to self lock in the apertures.

11. A bobbin substantially as hereinbefore described with reference to the accompanying drawing.